Roger Federer gave another hint that he may yet be a factor in the later stages of the US Open by brushing aside Carlos Berlocq in the second round.
The five-time champion is seeded only seventh after a poor season and has not reached a grand slam final since winning Wimbledon last summer.
Much stiffer tests await but Federer struck the ball well in a swift 6-3 6-2 6-1 victory over Argentina's Berlocq on Arthur Ashe.
His final match before the tournament was a quarter-final against Rafael Nadal in Cincinnati, which he lost in three sets but showed enough of his old magic to make the obituaries seem slightly premature.
The pair could yet meet again at the same stage here.
Nadal remains undefeated on hardcourts this year after crushing Rogerio Dutra Silva of Brazil 6-2 6-1 6-0 to storm into the third round.
The second-seeded Spaniard improved his hardcourt mark to 17-0, a run that has brought him tournament titles at Indian Wells, Montreal and Cincinnati among his nine trophies in 2013.
Nadal faced only one break point in the 92-minute rout on Arthur Ashe Stadium's center court, ripping 30 winners to just nine.
World number two Nadal, who missed the 2012 US Open because of a knee injury, will next play Ivan Dodig of Croatia, a 6-1 6-4 6-4 winner against Russian Nikolay Davydenko.
"One match against Rafa is not going to make my season or going to make me super confident or not" - Roger Federer
Federer said: "For me, one match against Rafa is not going to make my season or going to make me super confident or not. It needs to be more than that.
"It hadn't been actually a terrible season up until Wimbledon really, and Wimbledon was just a disappointment. I wish I could have played better, but I thought (Sergiy) Stakhovsky overall played pretty well. Let's give him some credit, too.
"After that, I just really hoped I could win Hamburg and Gstaad back-to-back to gain confidence. It never really happened.
"For me it was just playing matches again, enjoying myself training really hard, and I really got the matches I was looking for in Cincinnati, and I'm still hopefully gaining confidence match by match.
"As we know, it might not just take a match but it might take just a few matches, and next thing you know you're playing really, really good tennis again and you're close to playing some really great tennis.
"I think that's kind of where I am right now, and that's where every match is really important to me and how I play every single point."
Fourth seed David Ferrer is another man trying to find his form, and he dropped a set against his fellow Spaniard Roberto Bautista Agut but came through 6-3 6-7 (5/7) 6-1 6-2.
There were straight-sets victories for Richard Gasquet and Janko Tipsarevic while British qualifier Dan Evans continued his New York fairytale by knocking out Bernard Tomic 1-6 6-3 7-6 (7/4) 6-3.